Radio frequency (RF) power amplifiers are used extensively in the wireless communications industry. Using a typical RF power amplifier, an input baseband signal is modulated, amplified, and transmitted as an RF signal. To generate the RF signal, an analog input signal is first processed by a baseband processor to generate an in-phase (I) signal component and a quadrature (Q) signal component. The I and Q signal components are processed and mixed to form the RF signal.
An RF signal can also be generated using polar modulation, where the input baseband signal is converted to an amplitude modulation (AM) signal component and a phase modulation (PM) signal component. In a polar modulator, the AM signal and the PM signal are processed separately before being combined to create the desired signal.
Early power amplifiers processed input analog signals without any digital conversion. Appropriately processing and modulating analog signals is difficult to achieve. As digital processing has evolved, power amplifiers have included digital processing components along with traditional analog signal processing. However, absent a complete digital implementation, digital to analog conversions, such as those performed in an amplitude signal generator, introduce large discrepancies. In general, methods of improving the digital-to-analog and analog-to-digital conversion process are always needed. In particular, methods of improving the digital-to-analog and analog-to-digital conversion process within polar modulators are also needed.